MPCNC Version 2 -opinions-

New Home Forum Updates MPCNC Version 2 -opinions-

This topic contains 434 replies, has 66 voices, and was last updated by  Jakob A 3 months, 1 week ago.

Viewing 30 posts - 61 through 90 (of 435 total)
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  • #8754

    Ryan
    Keymaster

    Okay so Matt just emailed me about Chromoly, 4130. Anyone have any experience with it?

    It cheaper than stainless, decent rust resistance, designed/sold as structural tubing. What is the down side? Same stuff in bike frames and airplanes right?

    Maybe I’ll take a road trip and try and hunt some down.

    #8808

    Ryan
    Keymaster

    New corner, I hope.

    An opinions?
    +This seems stronger, than the current one and a few others I have prototyped mostly in the leg side.
    -Takes 1 more screw and nut. bummer
    ++Each corner set takes a little more than 4 hours less, and 33g less plastic to print!! 17 hours less total, might get this under 100 hours soon.
    +I made this easily editable for me to make multiple versions for different tube sizes.
    +No more glue!
    +A little more style??
    +Still no support.
    +Gain about 10mm travel per axis or more.
    –all 4 corners are no longer symmetric, there will have to be a corner A and a corner B.

    Well, let me have it, constructive criticism appreciated.?
    https://www.dropbox.com/s/w8aheb61yybqp4f/corner5.avi?dl=0

    I know most of you guys want a new center assembly, and I am working on that as well but I have never been very happy with those corners. Using glue is such a cheat, Although I might add a little glue hole so some of you quit cranking down your parts so hard. That way you could get everything set and aligned and then add a drop of super glue to “locktight” it in place instead of trying to over tighten or modify the parts.

    Attachments:
    #8815

    MJ
    Participant

    I dig the new corner. Any problems with fitment of that bottom piece to the main part? Have you created a WIP page on Thingiverse for the new parts/version? So far, I love the fact it takes less plastic and print times are shorter. Looking good!

    #8820

    Ryan
    Keymaster

    Thanks.
    The bottom piece is just like the top but has a little style(maybe?). 2 screws hold it on, made sure you could get t the other screws without removing it.

    No new thingiverse page yet, I still get emails with people asking why there corner blocks don’t look like the ones on the assembly page. I like making parts, hate taking pictures and all the rest of it. Keeping all this info up to date is hard. That and None of this is final until I finish the center. I might have to change the distance between the rails.

    #8822

    nerdyrcdriver
    Participant

    That new corner design looks awesome! Hoping to assemble a machine for my workplace this summer for basic prototyping. Couldn’t convince the boss to get an x carve, and we probably have all of the electronics besides the ramps board. The corner looks much more refined and looks like there is practically no support required.

    Have you considered reaching out to a nearby high school to see if there are any students interested in this kind of stuff? You might be able to find an assistant willing to help out. That’s how my boss found me. It started out non paid but I had unlimited creative freedom to build whatever I wanted with the prototyping stuff they had. Eventually I proved myself and got a job. I don’t know what you are able to offer to a student besides engineering knowledge, but I am sure you can find someone to help out at little to no cost. Maybe upgrade the forum? I love it, but it is kinda slow. I usually access it from a computer with a 500mbps up and down connection (advantage to my lab at school being in the basement where the internet comes in. I have a direct link before it goes through the servers and other stuff for the college) and with a connection like that you really start to notice which sites have a good server(s).

    #8834

    Aze Aze
    Participant

    Hi, i’m working on a corexy printer with 20 steel tubes and made these corners (the ‘big one’ will be on top of the printer, the economic one, with his symetric, at the bottom). Both are easy to print and tested: very stiff. The big one has some ‘GT2 belt’ insert to reduce the noise of the motor and to improve friction.
    It’s just to give you some ideas, in case of… But your new corners looks already pretty cool. And thanks for your work! (it’s my first post, I’m still printing my IE MPCNC, with his too wide holes for nuts and too small for nylon ones :=D ).

    #8843

    Walter
    Participant

    The new corner blocks look pretty slick. i wonder though if it wouldn’t be a bit more beneficial to actually make the corner blocks wider instead of narrower. you are already limited to travel by the center z assembly hitting the rollers and a wider corner would mean theoretically better squaring. but you are definitely onto something by making them use less plastic/time. I’ve been toying with taking your original design and making it taller, using 1 1/4 PVC for rigidity. still a work in progress. but it’s moving faster now that I finally bought myself a trackball.

    https://www.thingiverse.com/thing:1347166

    #8849

    Ryan
    Keymaster

    I am so close to getting this site blazing fast. I am sorry I know it sucks right now. WordPress and Woocommerce are extremely difficult to optimize even with the gigantic user base. The last piece of the puzzle is getting litespeed cache enabled on this site. I had it on for 20 minutes or so yesterday and man this thing loaded intsantly, it was freaking amazing! Every page just popped up as soon as you clicked the link. All the tools pingdon, insight, gmetrix showed easily under 3 second initial page load, down from 6-9 seconds.

    The problem is PHP requests for the page template, WP an WC all hit the server hard, and this site is getting pretty steady traffic now. Lite speed caches these momentarily.

    But….if anyone tried to log in at that time they got logged in as me! I had all the rules in place not to cache login pages admin pages ect, didn’t matter. I will keep trying. I have seen the light at the end of the tunnel and I want it!!!!

    #8850

    Ryan
    Keymaster

    I love the gt2 belt inserts, awesome idea!!!!!!

    Both those deigns are amazing actually. I have been designing and printing test pieces out for months now. So when I say amazing I mean it. I choose the keep the leg under the horizontal bars to maximize cut area and minimize footprint.

    So for me this is 2 fold. You can overcompensate to get things to work or you can optimize. I have always been the optimizer (and I want to cut down on over all print time). The corner blocks on this machine don’t do much, they hold a belt and maintain the tube separation. There is very little actual force, because there are 4 of them. these really are still very much overkill. I want to make them smaller but I know people don’t believe it. Judging by all the “strong” remixes of all my parts on thingiverse.

    #8851

    Ryan
    Keymaster

    So these actually have more contact area on the leg and top tube, effectively making them wider. The middle tube loses out a bit but really it is over kill. I had another on ready to go super minimal and it worked great, but I new it would not be well received. So this is the middle of the road for me.

    That roller hitting is exactly why I said this should gain 5mm on each end if not more. I got the plastic out of the way of the rollers. Over all smaller footprint, I hope, when I put one together I will know for sure.

    The other one was fine but I feel this makes the leg connection much better and should keep all 3 axis at 90 degrees from each other much better.

    #8852

    Walter
    Participant

    I don’t have issues with the rollers hitting the blocks. My build size is directly proportionate to the a out of space between the rollers and the ends of the middle assembly are what determine where my endstops go and my endstops are about 4 inches from the corner.

    #8853

    Walter
    Participant

    I can deal with it being slow, is there a checkbox somewhere that will return me to the page I was on when I login, other than hitting back back refresh

    #8854

    Ryan
    Keymaster

    I know I hate that. I’ll keep looking into it.

    #8856

    Ryan
    Keymaster

    That’s the minimum, the other end, maximum, you should be hitting the corners,

    #8857

    Walter
    Participant

    Yeah, but i find that the last bit of belt can be a bit skewed depending on how you have your belts tied on. I found a belt end that fits perfectly up against he cornerblock as it is so its not an issue for me, but I have seen some other builds where the belts don’t exactly line up to plane with the roller. not an issue until you try to get up close to the corner. i see your new design was built with the belts in mind and I like that.

    #8858

    Ryan
    Keymaster

    Always been that way, there should be plenty of room. That is why I don’t promote many of the “upgrades” When there is a reason they won’t work or will make my design not work well I PM the designer and tell them. Most if not all publish them anyway.

    My rollers hit the screws, so I moved them.

    #8860

    Walter
    Participant

    https://www.thingiverse.com/thing:1272787

    This is the belt holder I am using. by negating the cap portion of it, I find that my belts stay flush to the corner block and they plane off very nicely with the roller bearings. and they are easily tightened using the zip tie.

    #9051

    Zack
    Participant

    Hey Vicious, I checked out the stainless tubing from Ace hardware that you found and on their site it says that it is 1 inch. I saw that you mentioned earlier that it was 25mm. I was just wondering if they are marketing it as 1 inch, and it is in fact 25mm? When I get the chance to personally go to my local Ace I will be sure to measure it to confirm.

    #9057

    Ryan
    Keymaster

    I’m not around to measure it right now. Just to be clear, It is not as rigid as the conduit. That is more for a , “look around” type of thing. I do not recommend it at all.

    #9149

    Nick
    Participant

    So I don’t know if any one else has tried this little trick to increase rigidity?
    I modified the middle z rigid to not have a Z component and added it to the opposite cross section.
    This made a huge difference for CNC cutting using a 52 mm 300 watt spindle from inventables, off my old shapeoko
    Back cross section

    The trade off is that it increases dead space but definitely worth it.

    I have published the new middle Z Rigid that does not contain the Z component.
    New Middle Z on thingyverse

    Note this could be done by also reprinting a second middle assembly but without the component above it increases the dead space

    Just curious if anyone else has tried this I’m seeing really good results.

    #9232

    geodave
    Participant

    I would really like to see a way to tension the belt on your corner design. The wire ties do not give you as much flexibility as using a bolt and nut.

    #9236

    Ryan
    Keymaster

    Many people do seem to like extra hardware, but I have never understood that. What is the draw of extra parts? These cable ties easily hold 40lbs of tension and adjust in 1mm increments. I set up a machine run it for a few hours or a day, then come back and give each one an extra click and its set, never to be re tensioned again.

    On the new corners I can easily make that a hole instead of a cable tie slot then you have to deal with screw and nut sizes which differ around the world and at least 4 more extra parts?

    Cable ties, duct tape, Velcro, super glue, all champions of my shop!

    #9247

    geodave
    Participant

    Just a suggestion. I am probably not able to tighten the cable ties as tight as you. With a bolt & plastic clamp to hold the belt, I can easily tighten or loosen the belt with little effort. Seems like on the longer versions of this machine it would be more difficult to tighten the belt with just the wire tie.

    #9249

    Walter
    Participant

    In my experience, unless your belts are just too long, once the tie gets hard to pull, you should be done tensioning. it’s not necessary for it ring Esharp when you pluck it. over tensioning can cause you to skip steps.

    #9250

    Ryan
    Keymaster

    I like the suggestion that’s why I started this thread. I think I can make that a combo slot/hole so you could do either.

    My belts really aren’t that tight, I don’t think I even use plies to pull on the cable ties. Hand tight I’m pretty sure. Even with that one of my motor mounts has 40% infill and it is bending. There have been a few threads where people have tightened there belts so tight with the screws that there steppers wouldn’t turn. I think that was the one with the eye bolts, people were using a wrench to tighten it.

    #9252

    Walter
    Participant

    Oh don’t get me wrong it’s a great idea to build in a tensioner so you aren’ relying on zip ties, just that they don’t need to be too tight.

    #9254

    Jason
    Participant

    Interesting add on Nick.

    Would definitely like some more info on how you mounted this… Cannot have too much rigidity in the Z axis.

    #9274

    MJ
    Participant

    Here’s a thought for V2…have you considered rotating one of the carrier rails? In other words, rather than have the Z intersect with the X and Y axis, it could ride on two parallel rails along one axis. The Y-axis remains as is with a stepper on each side, riding on a carriage that holds two rails instead of just one. The X-axis runs along those parallel rails with a stepper at each side. Those steppers would move with the Y-axis, but not with the X. The belt ends would attach to the X carriage above the rails and route through the rails via idler pulleys on each end to return. If nothing else, it might mean fewer parts than the current middle Z.

    Attachments:
    #9279

    Ryan
    Keymaster

    I’ll have too look at that. The only immediate problem I see is the tool size is limited by the rail distance, not a deal breaker. Put the X drivers back on the head to eliminate the looped belt.
    Nice.
    The easiest way to analyze these things is exaggerate all axis and look for the obvious weak points.
    I like it.
    thinking about the z

    #9287

    MJ
    Participant

    Yeah, that is a limitation for those people using really big stuff. Maybe this would appeal to the printer/laser crowd. In any case, it might help to simplify the Z a bit. As for the X-axis belt loops, I figured that could be an issue with wider machines – long belts = potential stretch. Again, maybe more suitable for smaller builds. My thought was to remove some of the weight/inertia from that axis, but I guess it really doesn’t matter. Just putting it out there.

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